Lubricant and method of making same



Patented May 5, 1953 LUBRIG AN-T AND METHODQOF'M AKING ASAME David'Frazier, Cleveland, Ohio, assignorito The Standard'TOil-fCompany, Cleyelandflohiwa corporation of Ohio fNo'xDi-awing. .Application"May!.;3.1,. 1950, nSeriaLNo. 165,382

12 Glaims. TI This invention relates to a method of improving the color and .odor stabilityof lubricants and lubricant additives an'dto the resulting improved lubricants and lubricant additives.

:In..order P to satisfy the public desire, a .lubrieating oil'should bezolear', and light colored and odorless. Thelubricating-oil, from thestandpoint of engine performance, must also :contain aneadditive which. inhibits deterioration ofg-the oil during use .in .an internal icombustion engine. The phosphorus sulfide osygenated.organia compound-olefin areaction products constitute one class of additives which give excellent resultsin theslatter. respect. lhese additives, .hwever,.-are darkerhcolored than the .oils and .theinaddition imparts a: darkercolor tolubricatingsoils. Moreovemthesesadditives. liberate ,hydrogen-sulfidaon standing, because of instability; of some of vthe chemicallyebound sulfur .contained :therein, and therefore toils containing such-additives become ionl smelling in use-or rafter. storage. ifIhe dark color I :and the hydrogen sulfide liberated ifrom such -iadditives-containing -oils :deters .the public frompurchasing themin the guantitiesltheir m1- uable performance characteristics should ensure.

:Typicalof this class of'additivesare vthosefidescribed and-claimed in U. S..Patent No. 2,566,241 of John l-Musselman, .dated August 28, .1951, wherein -is; disclosed a process of, preparing. these additives Joy-reacting a mixtureof.,1\ to .10 parts of a .pelyolefin 4- capable of improving the .viscosity indexrof a luhrieating oil and .1 part of an oxygen-icontaining. organ-icwcompound: having. .a'i boilill point of 1east225 with a -.phos :horus sulfide at; a v.tenmperatine in the .range of 225 :to

500 F., in proportions such that the .reaction product @thereby obtained contains .5 .to .60 5 by Weightof-a;phosphorussulfide and95 .to 40% of the 1OX-Yg6n-C01'it2tllfll1lg organic .compoundepolyolefin mixture.

-The presentdn'vention .isdirected .to the improvementofthe :color andodorstability of these reaction products by treatingthe samewith an alkali hydroxide in 1 the range of 0.125 .to 01715 by weight and sufficient to improve ;the .color thereof, -;followed by treatment with .-hydrogen peroxideinan amount in the range .of .015 to 0.5 %'='byweight. and sufficientto. improveflthe odor stability .of the reaction product.

vIthas been demonstrated that treatment of such-reaction-;products with an alkalihydroxide alone givesa considerable color. improvement, and that. oils tcontaining the hydroxide etreated additive darken Jess than the untreated .oils .after heating .tor' three days at .150 "L'Ihe. stability against .odor formation .is also .improve'disome- :what. It has also been 'demonstratedthattreatment of such reaction'products .with hydrogen peroxide alone markedly imprcvesthe odor'stability "but gives a product having a considerably darker "color. and poorer 'color' stability than the untreated product. In fact, thecolondeterioration which "resultsffrom the hydrogen peroxide treatment alone "exceeds .the color improvement obtained byhydroxide treatment-alone, so that it would be 'expectedthatthetreatment of a hydroxide treatedadditivewith hydrogen peroxide would :degrade the "color toa "point where the treatecladditive is darkerthan the untreated additive. 'Surprisinglmhowever; the, datashow' that the coloryas measured by-optical density, isbetter "after "the Jcombined treatments than -after treatment with 'hydroxide'alone. Moreover, 'the hydrogen sulfide"developed is considerably less than "Whentreated Wit'h'hydrogen peroxide alone, thus demonstrating the improved odor stability or the product of 'theinvention.

The objectsa'chieved in accordance Withthe inventi'on include the provision of an agent of im-' proved colona'rid- 'odor sta'bilitywhich maybe useful "itself 7 as a Y lubricant; and 'which "when added to lubricants will improve theyiscosity index and alsomarkedly inhibit'the very obj eotionable' deposition of lacquer, and; at 'the -same' 'time, inhibit acid and sludge "formation, corrosion andtother types of deterioration occurring underxoperating conditions; the *provi'siom of? lubricating" oils icontainingsuch an addition agent; and other 10bj'ectswhich "will be apparent as embo'diments 1 of theiinvention" are disclosed hereinafter.

The reaction *product 'treated in accordance with "the invention may 'b'e madewith directedniix'ture o'f the "reactants, or, if desired, by their admixture in the presence cfradiluent which may or may not 'be subsequently removed. Aheavy oilysuch aswhite oilgorsalubricatingroil having aboutthe'same 'properties as th'atto which'the new-= composition is to be added may-*be'used as a diluent. Oil maybeadded'aftercthe:reaction such as during a subsequent filtration. The reaction isusually complete in about 1.0- hoursuor less time, generallyfl to 2 hours. "'Theireaotion time is '-a function of the temperature, i'th'e amount '1 of a the sulfide that is" to='reac't, the subdivision of .the reactants, the efiiciency of mixing, 61.10.

The mixture o'f polyolefin and mxygen-containing organic compound may be 'rreacted with the iihosphorus sulfide :or i a :mixture :of phosfihorus sulfides kin ':ratios from :5 -.to :about weight 'pe r oent 'ot the phosphorus asulfide based on the Weight 'o'f the=above rniixture, depending on the type of mixture. ifieneraliwabout is -to about 50 percent-. is the usual :range :that will be used, depending son "the ;molecular weight .of

the polyolefin and its proportions relative to the oxygen-containing organic compound, and about to about 20 per cent is especially desirable.

Phosphorus pentasulfide ispreferred although other phosphorus sulfides or mixtures of sulfides may be employed. Phosphorus pentasulfide is most economic and readily available and for this reason is used in the illustrative examples.

The polyolefin which may be used is one which improves the viscosity index of lubricating oil, e. g., one having a molecular weight of about 2,000 to 100,000 and which is soluble in lubricating oil, These materials are substantially saturated as the art will appreciate. As mentioned above, such materials are known in the art. The

commercially available material is known as Paratone which is a polyisobutylene polymer of 10,000 to 20,000 molecular weight in such amount in a solution of oil as to givea viscosity of about 3,000 S. U. S. at 210 F.

An ester wax such as degras. lanolin or sperm oil is a preferred oxygen-containing organic compound. In the broader aspects of the invention, there may be used such a compound containing hydroxy. carbonyl, or ether oxygen, and desirably one of rather high molecular weight, preferably boiling above the reaction temperature, e. g., at least 225 F. The reaction may be conducted under pressure, if desired, in the case of lower boiling materials. There may be used esters, as alkyl or cycloparai'fin or aryl esters of organic acids: fatty oils, higher alcohols. higher carboxylic acids, saturated and unsaturated, monobasic and dibasic, petroleum acids, naphthenic acid, rosin, modified rosin, glycol ethers, higher ketones and aldehydes; also halogenated derivatives of any of these. Illustrative of some conveniently applicable materials are: beeswax, lanolin, sperm oil, other waxes, butyl stearate, ethyl lactate, methyl oleate. butyl ricinoleate, butyl phthalate, methyl stearate, methyl dichlorostearate, methyl chloro-naphtenate, dichloropalmitic acid, coconut oil, babassu oil, hydrogenated coconut and other vegetable oils. other fatty oils, ethylene glycol monoethers, diglycol chloro-hydrin. lauryl alcohol, stearic acid, lauric acid, oleic acid, palmitic acid, myristic acid, naphthalic acid, naphthoic acid, benzoic acid, naphthenic acids, hydroxystearic acid, dihydroxybenzoic acids, hydroxynaphthenic acids, dihydroxystearic acid, chlorobenzoic acid, dichlorostearic acids, dichlorobenzoic acids, dichlorodihydroxystearic acid, lactones. palmitone, oxidized petroleum fatty acid or other petroluem product, as oxidized wax, kerosene, gas oil or other oxidized petroleum oil. The oxygenated compound used in forming the reaction product should be selected with reference to the use of the final composition and properties desired in it, e. g., to give a reaction product having oil solubility or dispersibility.

In the illustrative embodiment it is preferred to use about 3 parts by weight of the polyisobutylene oil solution available as Paratone with about one part by weight of the degras or other oxygenated organicmaterial. If the Paratone is assumed to be a 40% to 50% solution in oil, this would be about 1.2 to 1.5 parts of the polyisobutylene to one part Of degras. However, widely different proportions show significant improvements and an amount of polyolefin in the range of 1 to 10 parts by weight to one part of the oxygenated material is desirable.

inert or non-deleterious gas, such as nitrogen or Has. It may also be carried out under pressure, e. g., the pressure generated when the reaction is carried out in a closed vessel.

The reaction temperature varies with polyolefin and oxygen-containing compounds and is readily ascertained. The optimum is in the range of 225 to 500 F., although a higher temperature which is below that at which the reaction product would be decomposed could be used. A temperature of at least 250 to 300 F. is preferred in many cases.

An element of the sulfur family, i. e., sulfur, selenium or tellurium, can be incorporated into the reaction product by adding elemental sulfur or a compound which yields sulfur, such as by treating a derivative of the sulfide-derived reaction product therewith, or treating a derivative of the sulfide-derived reaction product. therewith.

In accordance with the present invention, the resulting reaction mixture is treated with an amount of alkali hydroxide sufiicient to improve or lighten the color thereof. Generally, this will be in the range of 0.1 to 0.75% by weight of the reaction mixture. The alkali hydroxide preferably is in the form of an aqueous solution,such as a 50% solution, although the solid hydroxide may also be employed. Alkali hydroxides which have been found to be suitable are potassium hydroxide, sodium hydroxide and ammonium h'y droxide.

The reaction mixture is mixed and heated with the alkali hydroxide at a temperature in the range of 160 to 220 F., referably about 200 F. and for a time in the range of 15 minutes to 2 hours, p'ref erably one-half hour. During reaction the reaction mixture is preferably blown with an inert gas, such as air or nitrogen, to remove water formed in the course of the reaction and/or added with the alkali hydroxide. If water is present in the additive when added to an oil, a cloudy solution is obtained. This is prevented by the blowing step.

Then the reaction mixture is treated with hydrogen peroxide in an amount suiiicient to improve the odor stability thereof, particularly as measured by the formation of hydrogen sulfide on heating. Generally this will be in the range of 0.15 to 0.5% by weight of the reaction mixture. The peroxide ordinarily is added in the form of an aqueous solution, preferably a 30% solution. Aqueous solutions of hydrogen peroxide or sodium peroxide are satisfactory sources of hydrogen peroxide.

The reaction is carried out at a temperature in the range of 160 to 220 F., preferably 200, and for a time in the range of 15 minutes to 2 hours, preferably one-half hour. Air or inert gas is preferably blown through the mixture during reaction in order to remove water therefrom for the reason stated above.

The amount of the final reaction product (i. e.. the additive) to be incorporated in an oil or grease will depend upon the characteristics of the oil or grease and the intended use. Some oils have more of a tendency to corrod metals, or to form acids, sludges and lacquer deposits than others, and such oils require larger quantities of the addition agent. Also, oils that are intended for use at higher temperatures require larger amounts of the additive. In general, the range v is from about to about 10%; under some cir- The reaction may be carried out in the presence or absence of air, or in the atmosphere of cumstances, amounts as low as about 0.01% show a significant improvement. Since the provided reactioapmdue s a lu icantth re is no upp r imit. However, it may be uneeon mioal o nclude in ev ubr c nt e of h p id d re action product than necessary to impart the des red pro iese eh a 0% The following examples and tests illustrate and point out advantages of the invention and also the criticality of the ranges of alkali hydroxide and peroxide:

Example 1 Twenty parts by weight of Pass i mixed with such portion of 100 parts of a neutral diluent lubricating oil lbs. per barrel aoidetreated lubricating oil stock having a viscosity of 225 S. U. S, at 100 F.) as to form a slurry and this is mixed with a mixture of parts of degras and parts of the above-described Paratone. The balance of the 106' parts of the neutral diluent oil is added and the mixture agitated for one hour at 305 to 310 F.

To a gram sample of this reaction. mixture there were added the amounts of 50% commercial potassium hydroxide indicated in the following table. The samples were then heated to 200 F. and blown with air at that temperature for one-half hour. Other samples were treated by adding the indicated amount of 30% aqueous hydrogen peroxide solution and blowing the reaction mixture with air at 00 F. for one-half hour. Other samples had both treatments as shown in the following table. Various test on the samples were made as indicated in there}- lowing table with the results shown:

hydroxide and hydrogen. peroxide. These are c mpute y corre t ng the r sult tf sampl 1 o 4. 0 and lfiiwhich how hat tr a ment with hydr en pero id ne ees s. he oa h al density b llpe nt a t tme w h 3% hydro en peroxide by 1 o s, e p c ively, wh l t eatm n th 9. 5% po as ium 13 393. e duc s th p al d i y by 5 p nts. i h 0.25% potassium hydroxide by 24 points, with 0.375% potassium hydroxide by 28 pointsv and with 0.5% potassium hydroxide by 26 points.

The optical density found for Samples 5, 6, 8-, 9, 11', 12, 14' and 15 show that contrary to what would he expecteda reduction in color is obtained greater than with the potassium hydroxide treat.- me a ne:

Tha r atmen ith 0.15% y o en er xi and 1. 5% p ta s um hyd xide s th de irab lower limit of concentration of these reactants is demonstrated by the results obtained in Samples 5 and 6. The color improvement in these samples is not as satisfactory as in the latter samples where more potassium hydroxide and'hydrogen peroxide are used. That 0.5% potassium Treatment Additive Analyses 4 Percent Additive in No. 20 Motor Oil 0 m ce D n y Neutralization Number Saponification Number Percont S Per.-

KOEU cont 1? Hydrogen Sulfide, (p. p. m.)

After 1 day at After B'Days 11. Alter 1 at;-

Day At 150 F.

Original Expe te 150 F.

* (3/1 00 g. samples.

Sample No. 1 shows that the increase in optical density and hydrogen sulfide content after heating the untreated additive at 150 F. for one day and for three days, respectively, quite high. Samples 2 and 3 show that the hydrogen peroxide treatment alone is eiieotive in reducing the h dro n su fid c n b t a k e red as evidenced by the increase in the optical density, to a value greater than thatof the untreated product. Samples 4, 7, 10 and 1-3 show that treatment with potassium hydroxide alone improves the color and also reduces the hydrogen sulfide content, but in the latter respect is not nearly as good as hydrogen peroxide.

From the optical. densities of these samples there is computed the optical density that would he expected for Samples 5, 6, 8, 9, 10, ll, 12, 1.4 and. 5 y treating m with bo po assium with 0.25% and 0.3'Z5% potassium hydroxide and 0. a d 9-.3% d gen pe xide. as shown in S p eh 9, l a 1. a d w th 05% Po a i ydro p roxide. as

brew ie nd 0 15% shown E1 Sam e-1 addi ional advantage of the treatment is shown whenwater. isadded to the additive after heating the same for three days at, 150 F. The untreated additive showed a sharp increase in the evolution of hydrogen sulfide from 12.1 to 22.2 parts per million whereas Sample 12 only increased irom 3:0 to 3.6 parts per million. This shows that the additives treated in the method of the invention give little or no increaseinthe evolution of hydrogen sulfide when wet; Thiszis especially important since the additives are often su je ted to Water whi hmar c umul te n h c ank ase o ane eine- Example 2 Example 1 was repeated, treating the additive with flake potassium hydroxide rather than 50% aqueous potassium hydroxide solution. The product obtained showed a reduction in hydrogen sulfide content from 46.3 to 19.6 parts per million after three days heating at 150 F. The color as measured by the optical density was also improved.

Improved hydrolyzable sulfur type additives are also obtained by treatment in accordance with the invention by a procedure similar to that set forth in Example 1 of additives containing oxygenated compound, other than degras, such as Comparable results are also obtained using additives formed by reaction with other polyolefins or other oxygenated materials, or other phosphorus sulfides or mixtures thereof.

Example 8 In another set of experiments, the additive" prepared in accordance with the processset forth in Example 1 was treated with 0.5% potassium hydroxide at 200 F. with air blowing for onehalf hour, followed by treatment with 0.3% aqueous 30% hydrogen peroxide solution at 200 F. for one-half hour with air blowing to remove water. The treated sample showed a hydrogen sulfide reduction from 49.1 to 18.7 parts per million, and a lighter color.

It is essential that the reaction products treatedin accordance with the invention be treated first with alkali hydroxide and then with hydrogen peroxide. Treatment with both reagents simultaneously or with hydrogen peroxide first and with alkali hydroxide second, does not give the improved results noted heretofore. The products so produced are much darker in color than the starting material, and smell strongly of hydrogen sulfide, indicating poor odor stability.

The lubricant additives prepared in accordance with the invention are suitable for use under various conditions, including high temperatures or high pressure or both; as, for instance, when incorporated in a motor oil for use in an internal combustion engine operating at high temperatures and in which the lubricant is in close contact with metallic surfaces, metal compounds and high temperature gases. They are also suitable as extreme pressure lubricant agents in oils and greases.

If desired, the additives of the invention may be used together with the other oil addition agents, e. g., pour point depressants or film strength agents. In some instances, it is desirable to include in a lubricating oil containing the additive an agent for improving the clarity of the oil, e, g., lecithin, lauryl alcohol, and the like, which are known to the art In order to prevent foaming of the oil containing a small proportion of the additive, it is desirable in some cases to add a very small amount of tetra-amyl silicate, an alkyl ortho carbonate, ortho formate or ortho acetate, or a polyalkyl-silicone oil, which prevent foaming upon the bubbling of air through oil containing a few per cent of the additive.

It is intended to claim the invention broadly, except as limited by the following claims.

The term hydrogen peroxide compound used in the claims includes hydrogen peroxide and compounds yielding hydrogen peroxide, such as sodiumperoxide.

I claim:

1. A method of improving the color of lubricants and lubricant additives which are reaction products of 5 to 60% by weight of a phosphorus sulfide and to 40% of a mixture of one part by weight of an oxygen-containing organic compound selected from the group consisting of those compounds containing hydroxy, carbonyl, ether and carboxy radicals having a boiling point of at least 225 F. with 1 to 10 parts of a polyolefin having a molecular Weight of about 2,000 to 100,000 and capable of improving the viscosity index characteristic of a lubricating oil, reacted together at a temperature in the range of 225 to 500 E, which method comprises treating such reaction products with an amount of an alkali hydroxide in the range of 0.1 to 0.75% by weight of the reaction mixture and sufiicient to improve the color of the reaction product and then treating the resulting reaction product with an amount of a hydrogen peroxide compound in the range of 0.15 to 0.5% by weight of the reaction mixture and sufficient to improve the stability of the reaction product and recovering the improved reaction product.

2. Reaction products produced in accordance with the method of claim 1, characterized by improved color and odor stability.

3. The method of claim 1 wherein the polyolefin is of about 10,000 average molecular weight.

4. The method of claim 1 wherein the phosphorus sulfide is P235.

5. The method of claim 4 wherein the polyolefin is of about 10,000 average molecular weight.

6. The method of claim 5 wherein the oxygencontaining organic compound contains a carbonyl group.

7. The method of claim 6 wherein the carbonyl oxygen-containing organic compound is an ester.

8. The method of claim 7 wherein the ester is desras.

9. Reaction products produced in accordance with the method of claim 8, characterized by improved color and odor stability.

10. The method of claim 1 wherein the alkali hydroxide is added in the form of an aqueous solution.

11. The method of claim 1 wherein the alkali hydroxide is added in solid form.

12. The method of claim 1 wherein the treatment with an alkali hydroxide and a peroxide is carried out while blowing the reaction mixture with an inert gas.

DAVID FRAZIER.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,496,508 Watson et al Feb, '7, 1950 2,507,731 Mixon et al May 16, 1950 2,566,241 Musselman Aug. 28. 1951 

1. A METHOD OF IMPROVING THE COLOR OF LUBRICANTS AND LUBRICANT ADDITIVES WHICH ARE REACTION PRODUCTS OF 5 TO 60% BY WEIGHT OF A PHOSPHORUSS SULFIDE AND 95 TO 40% OF A MIXTURE OF ONE PART BY WEIGHT OF AN OXYGEN-CONTAINING ORGANIC COMPOUND SELECTED FROM THE GROUP CONSISTING OF THOSE COMPOUNDS CONTAINING HYDROXY, CARBOXYL, ETHER AND CARBOXY RADICALS HAVING A BOILING POINT OF AT LEAST 225* F. WITH 1 TO 10 PARTS OF A POLYOLEFIN HAVING A MOLECULAR WEIGHT OF ABOUT 2,000 TO 100,000 AND CAPABLE OF IMPROVING THE VISCOSITY INDEX CHARACTERISTIC OF A LUBRICATING OIL, REACTED TOGETHER AT A TEMPERATURE IN THE RANGE OF 225* TO 500* F., WHICH METHOD COMPRISES TREATING SUCH REACTION PRODUCTS WITH AN AMOUNT OF AN ALKALI HYDROXIDE IN THE RANGE OF 0.1 TO 0.75% BY WEIGHT OF THE REACTION MIXTURE AND SUFFICIENT TO IMPROVE THE COLOR OF THE REACTION PRODUCT AND THEN TREATING THE RESULTING REACTION PRODUCT WITH AN AMOUNT OF A HYDROGEN PEROXIDE COMPOUND IN THE RANGE OF 0.15 TO 0.5% BY WEIGHT OF THE REACTION MIXTURE AND SUFFICIENT TO IMPROVE THE STABILITY OF THE REACTION PRODUCT AND RECOVERING THE IMPROVED REACTION PRODUCT. 